Postrecall Surveillance Following a Multistate FREE

To the Editor: A previous US outbreak investigation associated cases of Fusarium keratitis with ReNu with MoistureLoc contact lens solution (Bausch & Lomb Inc, Rochester, New York).¹ That study suggested that the outbreak was from failure of the product to adequately disinfect after point-of-use contamination, rather than from intrinsic contamination with Fusarium. The results contributed to a cessation of US product sales on April 13, 2006, and a worldwide recall on May 15, 2006.¹ We report results of the postrecall surveillance performed to monitor the effect of product recall.

Surveillance used passive and active systems. Passive surveillance initiated during the investigation¹ was continued postrecall through July 15, 2006, although reports were accepted after that date. In the passive system, the Centers for Disease Control and Prevention requested local health authorities to investigate and report possible Fusarium keratitis cases reported by clinicians and patients throughout the United States. Confirmed cases had clinically consistent fungal keratitis, no recent ocular trauma, symptom onset after June 1, 2005, and a positive Fusarium eye culture. Active surveillance used the Active Bacterial Core laboratory-based surveillance infrastructure in California, Colorado, Connecticut, Georgia, Maryland, Minnesota, New Mexico, and Oregon.² In the active system, presumed cases (defined as incident-positive Fusarium eye cultures) were identified by surveillance officers at laboratories in each site's catchment area from January 2004 through December 2006; 3 sites did not provide data after July 2006.

Passive surveillance identified 180 confirmed Fusarium keratitis cases from 36 states and territories between June 1, 2005, and September 30, 2006. Diagnosis was prerecall (June 2005 through May 2006) for 172 cases and postrecall (after May 2006) for 8 cases. Active surveillance identified 9 preoutbreak presumed cases (January 2004 through May 2005), 32 prerecall, and 3 postrecall (Figure).

Passive surveillance identified 94% (33 of 35 isolates during the period of passive surveillance) of presumed cases identified by active methods. The prerecall and postrecall groups had similar percentages of females (67% vs 75%), contact lens users (97% vs 88%), and corneal transplantation recipients (35% vs 29%). Among the 160 reports with known solution use, any MoistureLoc use was reported by 79% (122 of 154) of prerecall cases and 33% (2 of 6) of postrecall cases. Any use of another ReNu product (MultiPlus) was reported by 25 prerecall and 0 postrecall cases; 9 of these reported use of both MoistureLoc and MultiPlus. Two case patients reported their reason for MoistureLoc use postrecall; both stated they were unaware of the recall.

The surveillance data document an end to the Fusarium keratitis outbreak within 2 months of the MoistureLoc recall and, combined with previous findings,¹ are consistent with the recall being an effective public health intervention to stop the outbreak. The rapid decrease in cases postrecall supports the finding that this was the only product associated with the US outbreak.¹ Cases identified after the recall were likely due to individuals continuing to use MoistureLoc after the recall or were not outbreak related. Investigations of Fusarium keratitis outbreaks elsewhere^3- 4 have reported associations with MoistureLoc, although 1 recent case-control study in Singapore⁵ reported an additional association with a second ReNu product.

Active surveillance of a well-defined set of laboratories allowed for comparison of presumed case counts preoutbreak, prerecall, and postrecall. The retrospective review of surveillance data supported June 1, 2005, as the outbreak start date, a date following the introduction of MoistureLoc to the market.¹ Heightened media attention from April 2006 through May 2006 could have resulted in an increase in case reports from both surveillance systems due to increased clinical testing and case reporting. Nevertheless, passive surveillance, which required case confirmation with clinical interviews, provided essential information regarding product usage, although it did not add to overall postrecall trend data. These results may be relevant for public health officials when using such sources of laboratory data in similar situations.